Iraqi Prime Minister "Nouri al-Maliki" called today for residents of the conflict-hit province of Anbar to "take a stand" against Al-Qaeda-linked fighters, as the U.N warned of worsening displacement.

Iraqi army continued to press assaults against militants who overran parts of the Anbar provincial capital Ramadi more than three weeks ago, while violence elsewhere in Iraq killed eight people.

Diplomats have urged Baghdad to foster political reconciliation to undercut support for the militants, but with elections looming in April, Maliki and others have taken a hard line and focused on wide-ranging security operations.

Maliki said in his weekly televised address "I ask the people of the province -- the tribes, the notables, and all who live there -- to be ready to take a stand, to take serious action against those dirty people, without making any sacrifices" .

He added, referring to Fallujah, another city in Anbar that is entirely in the control of anti-government fighters that "It is time to finish this subject, and end the presence of gangs in this city, and save the people from their evil".

Parts of Ramadi and all of Fallujah, both former insurgent bastions in Anbar west of Baghdad, have been in the hands of Al-Qaeda-linked militants since late December, the first time anti-government fighters have exercised such open control in Iraqi cities since the peak of the insurgency that followed the 2003 US-led invasion.

Soldiers, policemen and SWAT forces have combined with pro-government tribal allies in an offensive that continued Wednesday against gunmen holding several neighbourhoods of Ramadi, an AFP journalist in the city said.

Fallujah, meanwhile, was largely calm, according to another AFP reporter there.

The United Nations warned on Tuesday of "an exponential increase in the number of displaced and stranded families", with more than 22,000 families having registered as internally displaced.

The U.N said the actual figure was likely to be higher, as not all those who fled had registered. It said of those who had left, most had found refuge elsewhere in Anbar, but some had gone as far afield as the northern Kurdish region.

Violence elsewhere in the country, meanwhile, left eight people dead, security and medical officials said.

The deadliest incident occurred in Baghdad's western outskirts, where three mortar shells slammed into a residential neighbourhood, killing at least three people.

Attacks in and around the restive cities of Mosul, Tikrit and Kirkuk killed five others in all.

The latest violence brought to more than 700 the number of people killed so far this month, according to an AFP tally.

By comparison, fewer than 250 people died as a result of violence in all of January 2013.